This reduces `runc` output closure size, particularly when not part of a
NixOS configuration.
`procps` was added in 50e24b8e0a, with the commit message indicating
the purpose of adding `systemctl` and `busctl`, both of which are
provided by `systemd` and not `procps`.
Presumably `procps` was added to make `runc ps` work regardless of the
environment, but this incurs a significant cost in terms of closure size,
especially when `runc` is packaged into something other than a NixOS
system, such as a dev shell or a package that does not use `runc ps`.
The alternative for improving the closure size would be to trim `procps`
itself. Currently it has a `systemd` dependency that's a significant cost.
However, removing that would also change `ps` and therefore `runc ps`
behavior. Furthermore, it would put two `procps` variants into the closure
of NixOS systems, when installed there.
Considering the above and the fact that the best `ps` is already present on
NixOS and most systems, I consider it the best solution not to bundle it
with `runc`, and take it from the environment instead.
bb35cbc40e